BIOL1130 Lecture Notes - Lecture 10: Point Mutation, Proline, Lolium
7 Jun 2018
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Glean Use in Australia – survival of the fittest: Darwinian evolution in action in
real time over huge areas
• Glean is a pesticide/herbicide
o Has no effect on wheat
o Kills ryegrass and most other weeds infesting the young what crop
o Very safe to humans & environment
o Apply only 20grams/Ha
o Cheap and easy to apply
o Universally adopted
• Glean is an example of evolution in action
o Sprayed on trillions of Lolium plants across Australia and did not
eradicate Lolium. Rapid evolutions (10 years) of Glean resistant
Lolium plants.
o Glean is Chlorsulfuron
• Properties of Glean
o It is Chlorsulfuron
o It inhibits Acetohydroxyacid synthase (AHAS) in plants
▪ Which resides in the chloroplasts
• How does resistant Lolium resist Glean?
o The glean still entered the chloroplasts
o The glean was not metabolized by the plants
o The glean was not moved within the cells
o The AHAS had become resistant
▪ The DNA nucleotide point mutation
▪ The gene was sequenced
▪ The 197th amino acid is proline (CCC) in the susceptible
plants
▪ It is Serine (TCC) in resistant plants
▪ It was this single nucleotidemutation that changed the
plants from susceptible to resistant
▪ The plant has no fitness penalty for this mutation
▪
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